error[E0015]: calls in constants are limited to constant functions, tuple structs and tuple variants
  --> $DIR/issue-68542-closure-in-array-len.rs:6:13
   |
LL |     a: [(); (|| { 0 })()]
   |             ^^^^^^^^^^^^

error[E0080]: evaluation of constant value failed
  --> $DIR/issue-68542-closure-in-array-len.rs:6:13
   |
LL |     a: [(); (|| { 0 })()]
   |             ^^^^^^^^^^^^ calling non-const function `Bug::a::{{constant}}#0::{{closure}}#0`

error: aborting due to 2 previous errors

Some errors have detailed explanations: E0015, E0080.
For more information about an error, try `rustc --explain E0015`.